The vadose zone, also known as the unsaturated zone, is the region of the subsurface that lies between the land surface and the water table. It is characterized by soil and rock materials that are not fully saturated with water, but contain both air and water. This zone plays a crucial role in the movement and storage of water, nutrients, and contaminants in the soil, and is important for understanding groundwater recharge, agricultural irrigation practices, and environmental contamination. Research in the vadose zone typically focuses on studying the interactions between water, air, and soil particles, as well as the movement of water and contaminants through the unsaturated zone. This research is important for understanding and predicting groundwater recharge rates, the fate and transport of pollutants, and the impact of land use practices on soil and water quality. Studies in this area often involve a combination of field measurements, lab experiments, and computer modeling to improve our understanding of the complex processes that occur in the vadose zone.